Index: lldb/include/lldb/Host/posix/ConnectionFileDescriptorPosix.h
===================================================================
--- lldb/include/lldb/Host/posix/ConnectionFileDescriptorPosix.h
+++ lldb/include/lldb/Host/posix/ConnectionFileDescriptorPosix.h
@@ -131,7 +131,7 @@
   lldb::IOObjectSP m_io_sp;
 
   Pipe m_pipe;
-  std::recursive_mutex m_mutex;
+  mutable std::recursive_mutex m_mutex;
   std::atomic<bool> m_shutting_down; // This marks that we are shutting down so
                                      // if we get woken up from
   // BytesAvailable to disconnect, we won't try to read again.
Index: lldb/source/Host/posix/ConnectionFileDescriptorPosix.cpp
===================================================================
--- lldb/source/Host/posix/ConnectionFileDescriptorPosix.cpp
+++ lldb/source/Host/posix/ConnectionFileDescriptorPosix.cpp
@@ -118,6 +118,7 @@
 }
 
 bool ConnectionFileDescriptor::IsConnected() const {
+  std::lock_guard<std::recursive_mutex> guard(m_mutex);
   return m_io_sp && m_io_sp->IsValid();
 }